Treatment of syenites



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July 14, 1936.

J. H. WEIS TREATMENT 0F sYENITEs Filed May l, 1954 mm M l. E 0 H w P M u Y B 106. COIVIPOSITIONS,A

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yPatented July 14, 1936 Search Hmm PATENT OFFICE TREATMENT OF SYENITES Joseph H. Weis, Scranton, Pa., assigner to Feldspathic Research Corporation, New York, N. Y., a corporation of Delaware Application May 1, 1934, Serial No. 723,343

4 Claims.

'I'his invention relates to the refining treatment of syenites, particularly to the separation of syenites from various iron bearing mineral impurities with which they are commonly associated, in order to utilize deposits of this mineral for purposes other than those in which they have heretofore been employed.

Syenites are generally classified as (a) common, (b) p, t, (c) ne.pqheliotfmggigmpowrjpelni,yln My reniig method is wd'apt'ble in general all varieties; modication being necessary when non-iron bearing minerals are to be separated as in the case of corundum.

According to Pirsson & Knopf (Rocks and Rock Minerals, published by John Wiley & Sons, 1926), syenite has the same value as granite for all constructional uses. `In Arkansas, syenite is used as a building stone and, since it contains no quartz, it can be polished easily; furthermore, it resists heat during res, thus making it more desirable than granite in these respects.

Because the only known use for syenite is as building stone, this product must compete with granite and other similar rocks. When used for this purpose it commands a low price and, since sources of building stone are relatively abundant, most deposits of syenite have little value and are generally not exploited unless they possess some particular economic advantage over other deposits of building stone.

I have discovered new uses for these syenites. Through the use of my process, hereinafter described, it is possible to use thesesyeiitwgswn lpreparations, and dwhen fsed for these purposes, syenites command a higher value. Furthermore, the market for syenites is greatly broadened to include other industries such as pottery, porcelain enamel and la .www l \-..l wwlmgwism houg`h the mineral feldspar is used successfully in ceramics, syenites, after treatment with my process, are better suited than feldspar for this purpose, for several reasons. Feldspar contains an average of free quartz which acts as a diluent, lowers the grade, and by its presence increases the total cost of the product. Syenites contain no free quartz and after treatment with my process are in a pure concentrated form. Furthermore, the refined product is much more fusible and has a distinctly lower melting range than feldspar. This valuable property of rened syenite results in a saving of heat which is one of the principal items of expense in ceramic J coi-und ,w chemical contrm'gl'i' o the finished product. The preferred process will be described in connection with the accompanying drawing which is a diagrammatic iiow sheet showing an arrangement of equipment by which the process herein described and claimed may be carried out in practice.

In the drawing, I represents the deposit of syenite which may be quarried or mined by conventional methods. The most desirable type of syenite is the white variety, because the iron content of this type of syenite is usually considerably lower than the darker colored varieties, resulting in higher grade concentrates. The run-of-mine syenite, Without the usual hand selection and attendant high waste required in feldspar mining. is then crushed in jaw crusher 2, and a cone crusher in or er to produce a product resembling fine gravel. Thgmigpgrtions of this product are removed by screen 4- and the oversize or larger particles are then passed through crushing rolls 5 for further reduction in size. The roll product is subject to a sizing operation in screen 6 where the ne fractions are removed, as before, and the oversize directed to roll Crusher 1 where a further reduction in particle size is made in order to produce syenite of the desired grain size. Screen 8 is in closed circuit with roll 1 in order to produce a finished product, so far as sizing is concerned. The preferable procedure for gathering together the syenite of correct grain size is to collect the underslze from the various screens 4,6 and 8 by means of conveyor 20.

No fixed screen size can be arbitrarily laid down as final as the maximum particle size is determined by the crystallization of the syenite being treated. When the syenite is coarsely crystalline, sizing to 8 mesh may be suiiicient, but if the ore is finely crystalline a ner grain size is necessary, mesh for example. Since glass manufacturers generally specify a maximum particle size of 20 mesh for the raw `materials used in the batch, it is usually desirable to set 20 mesh as the ruling or maximum'size of the syenite ore. Screens 4, 6 and 8 are therefore fitted with wire mesh surfaces adapted to produce such a product. Furthermore, the use of a cone crusher and crushing rolls permits the production of a granular, sand-like product with a minimum of line dust. syenite ore, I have discovered, is more amenable to subsequent purification treatment when in such a condition. The presence of considerable line dust lowers the efficiency of the purification process because of the loss and the mechanical hindrance to magnetic separation.

An induction, rotary type ma netic sg'pmaramtgmrwum is preferably used for the re'lr'f o iron bear'- ing minerals from the syenite. 'I'he syenite ore is reduced to a granular condition/ of about minus 20 to plus 80 mesh preparatory to magnetic separation. For best results, the feed to this separator is closely sized by screen 9 to such sizes as, for example, minus 20 plus 30, minus 30 plus 60, and minus 60 mesh, as experiments indicate a decrease in tailing losses due to loss of liner portions of the feed by centrifugal action of the revolving magnetic rotors. However, it is to be understood that an unsized feed can be treated on the induction rotor magnetic separator, but, for the same capacity, the iron content of the concentrates will generally be higher and the recovery lower.

Other types of high intensity magnetic separators, such as the Rowand Wetherill type, can be employed, but the capacity is usually much lower than the induction type and, generally, the iron content of the concentrates is higher than Where induction type separators are used.

Should the syenite contain corundum, this mineral is effectively removed witliwgvity con-` centrating tables. Syenites have a. spe'ci' "gravtiwaout'fd whereas corundum has a speel cie gravity of 4.0. The distinctly higher specific gravity of corundum is therefore used to advantage in a gravity separation process. Corundum is especially harmful in glass, as it is extremely refractory and fuses with difficulty, thus causing ,seeds of unfused material.

The concentrates from the induction rotor magnetic separator III, (or gravity concentrator II, when corundum is present) are collected on conveyor 2l and placed in mixing or blending bins I3 whose capacity usually ranges from 80 to 100 tons each. The product before entering these bins is automatically sampled by the mechanical sampler I2 and after the composition has been determined'by a chemical or mineralogical analysis, the contents of the various bins I3 are `blended by using suitable weighing conveyors, such as the Hardinge belt feeder, or a volume feeder. These feeds empty on conveyor 22 which discharges on conveyor I9 for nal loading in railroad car` I8. Mixing of the contents oversize is returned on conveyor Il to the grinding mill,` and whose finished product passes to railroad cars IB." This nely ground syenite with` Concen- Onginal run-of-mme nephellne syenite tttreoscrsgm 59. 68 SiOa 62. 46 23. 48 A1201 23. 23 1. 09 FezO: 07 26 CaO 88 21 MgO 04 4. 68 R20 4. 16 9. 52 N aaO 8. 75 Loss 43 4Production per hour: 31/2 tons Recovery: 78.4%

Percent Screen test of feed to separators cgctrs Per cant It will thus be seen thatthe invention accomplishes the foregoing objects. The impurities in the various types of syenites are removed and the concentrates are more desirable and preferable to feldspar used for similar purposes.

It will be understood that variations in the process herein described and claimed, and in the steps thereof, may be made within the purview of the claims, without departing from the scope of the invention, and that such variations will be required by the character of the particular syenite to be treated, its impurities and by other cond' tions. ,2.,

The invention claimed is:

l. Process of treating syenites containing iron bearing impurities, which comprises reducing syenite ore to a granular condition of about minus 2O to plus 80 mesh and mawgmnmemtmig rating the iron bearing impurities from While in such granular condition.

2. Process of treating syenites containing iron bearing impurities, which comprises reducing syenite ore to a granular condition of about minus 20 to plus 80 mesh magneticnalwluyselpgngtthe bearing impuities rm said ore while in of the various bins is not necessary as this is ac-fmm such granular condition, andglrqignwding the nonmagnetic concentrate to a fine poviidiO 3. Process of treating syenites containing iron bearing impurities, which comprises reducing syenite ore to a granular condition of about minus 20 to plus 80 mesh, removing the fine dust produced by granulation, subjecting the granular syenite to magnetic separation of said impurities, and grinding the non-magnetic concentrate to a ne powder.

4. Process of treating syeniteslcontaining iron bearing impurities, which comprises reducing 106. COMPoslTloNs, t 593mm Hmm CQATING 0R PLASTIC. l

syenite ore toagranular condition, of about minus sentative sample of the contents of each bin, 20 to plus 80 meshmrmgmovng thwnumt pror the contents of said bins to produce a. duced by granulatioh', subecg the granular ving g. prewggteijniinedgoinpqsition and syenite to glegngggggmtinof said impurities, grinding the bleio-xiwd'xfi'able for 5 placing te"noxhne'tncentrates in sepa.- use lin the ceramic art. 5

rate bins, determining the composition of a repre- JOSEPH H WEIS- 

